If a, b are integers and |a-b|=8, which of the following is the smallest possible value of ab?
A) -16
B) 0
C) 16
D) 7
E) 40
The OA is B.
If we set a=4 and b=-4, then |a-b|=|4+4|=8. And ab=-16. Why is B the correct option?
If a, b are integers and |a-b|=8
This topic has expert replies
GMAT/MBA Expert
- Jay@ManhattanReview
- GMAT Instructor
- Posts: 3008
- Joined: Mon Aug 22, 2016 6:19 am
- Location: Grand Central / New York
- Thanked: 470 times
- Followed by:34 members
Hi Vincen,Vincen wrote:If a, b are integers and |a-b|=8, which of the following is the smallest possible value of ab?
A) -16
B) 0
C) 16
D) 7
E) 40
The OA is B.
If we set a=4 and b=-4, then |a-b|=|4+4|=8. And ab=-16. Why is B the correct option?
Your answer is correct.
ab is minimum if a = 4 and b = -4 OR a = -4 and b = 4. Option B (0) is correct if it were given that a and b are non-negative integers.
The correct answer: A
Hope this helps!
Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide
-Jay
_________________
Manhattan Review GMAT Prep
Locations: New York | Hyderabad | Mexico City | Toronto | and many more...
Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
-
- GMAT Instructor
- Posts: 2630
- Joined: Wed Sep 12, 2012 3:32 pm
- Location: East Bay all the way
- Thanked: 625 times
- Followed by:119 members
- GMAT Score:780
You're correct, -16 is the minimum. (Proving that is a bit more complicated, but with these answer choices we don't really need the proof.)
Either the OA is a typo or the stem itself is missing some qualifier.
Either the OA is a typo or the stem itself is missing some qualifier.
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7222
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
The smallest possible value of ab is the one in which a and b have opposite signs. In that case, the value of ab must be negative since positive x negative = negative. The only negative value given in the answer choices is A, -16. Thus, A is the correct answer.Vincen wrote:If a, b are integers and |a-b|=8, which of the following is the smallest possible value of ab?
A) -16
B) 0
C) 16
D) 7
E) 40
Answer: A
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews